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Wednesday, September 21, 2011

Life of Sea | Bowhead Whale(Balaena mysticetus) | People also know this big whale as Greenland right whale or Arctic whale. Bowhead whales got its name from its high, arched jaw that resembles a bow. Bowhead life in the Arctic Ocean and adjacent seas. They spend most of the summer in relatively ice-free waters of the seas bordering the Arctic Ocean. They are associated with sea ice throughout the year. Bowhead whales are circumpolar, ranging in very high latitudes in the northern hemisphere. They spend the winter in connection with the southern boundary of the ice and move north as the sea ice breaks and retreats in the spring.

The Bowhead whale has a robust, dark-colored body, no dorsal fin and a strongly curved jaw and narrow upper jaw. The baleen whales, the longest of a whale at 3 m (9.8 ft), small prey from the water tribes. The whale has a huge bony skull, which he uses to break through the Arctic ice to breathe.

Bowhead whales feed on plankton, including copepods, amphipods, euphausiids, and various other crustaceans. They consume about 2 tons (1800 kilograms) of food per day. As a baleen whale, it has a series of 325-360 fringed overlapping plates of baleen hanging on both sides of the upper jaw, just outside where the teeth would otherwise be located. These plates consist of a fingernail-like material called keratin that frays out into fine hairs on the ends of the mouth near the tongue. The plates are dark gray-to-black and have the longest baleen of a whale, measuring up to 14 feet (4.3 meters) in length and 12 inches (30 cm) in width. During feeding, a Bowhead whale skims through the water with her mouth open. As water flows into the mouth and the baleen whales, prey are trapped on the inside near the tongue to be swallowed.

Bowhead whale is a slow swimmer and usually travel alone or in small herds of up to six. While it can stay under water for as long as 40 minutes in a single dive, it is not considered a deep diver. The whales' behavior can be broken, tail strike, and spyhopping. The bBowhead whale is very vocal, and uses underwater sounds to communicate while traveling, eating and socializing. Bowhead make some long repetitive songs that may be mating calls.Historically, Bowhead whales were severely depleted by commercial harvesting. Commercial hunting of bowhead in the North Pacific began when they were discovered in the 1840s. Commercial whaling of bowhead effectively ended in 1921 when the global population of the species declined to about 3,000.

Bowhead whales are harvested by Alaska Natives in the Beaufort, Bering and Chukchi Sea. The number of subsistence whaling crews in Alaska rose from 44 to 100 between 1970 and 1977. During the same period, the average number of whales landed increased from 15 per year to 30 annually, and the percentage of whales beaten, but lost also increased, possibly due to an increase in inexperienced crew. The annual level of existence landings averaged 37 whales per year from 1990 to 2000. In 2006, 39 hit during the Alaskan Bowhead whales were hunting. Of that number, 31 whales were landed. Other threats Bowhead whales are ship strikes, entanglement in fishing nets, pollution, and anthropogenic noise, especially from offshore oil drilling.